Do Soaking Grains Reduce Oxalates? A Deep Dive

November 30, 2025 •

4 min read

Soaking grains has been a long-standing tradition in many cultures, and modern research confirms that this simple act can reduce antinutrient levels. But do soaking grains reduce oxalates specifically? Yes, research shows that this process can significantly lower soluble oxalate content, making your food more nutritious.

Quick Summary

An analysis of processing methods reveals that soaking can significantly lower soluble oxalate levels in grains. Soaking works by leaching water-soluble oxalates into the discarded liquid, enhancing overall nutrient availability.

Key Points

Soaking Reduces Soluble Oxalates: Soaking grains is an effective way to significantly lower soluble oxalate levels by leaching them into the water.
Combine with Cooking for Best Results: While soaking is beneficial, cooking methods like boiling can achieve the most substantial reduction in oxalate content.
Discard the Soaking Water: To ensure oxalates and other antinutrients are removed, it is crucial to drain and thoroughly rinse the grains after soaking.
Enhance Soaking with Warmth and Acidity: Using warm water and adding an acidic agent like lemon juice or vinegar can increase the efficiency of the soaking process.
The Benefits Outweigh Concerns: For most healthy individuals, the potential negative effects of antinutrients like oxalates are far outweighed by the overall health benefits of consuming whole grains.

Understanding Oxalates and Their Impact

Oxalates, or oxalic acid, are naturally occurring compounds found in many plant-based foods, including grains, leafy greens, nuts, and legumes. For most people, consuming oxalates poses no significant health risk. However, they can bind to minerals like calcium, iron, and zinc in the digestive tract, forming insoluble compounds that inhibit their absorption. This is why they are often referred to as 'antinutrients.' For individuals prone to kidney stones, high oxalate intake can be a concern, as oxalates are a primary component of the most common type of kidney stone. Therefore, finding effective ways to reduce oxalate levels in food can be beneficial for certain populations.

The Science Behind Soaking and Oxalate Reduction

Soaking grains and other seeds in water is a time-tested technique for improving digestibility and nutrient absorption. The primary mechanism for reducing oxalates through soaking is a process called leaching. Soluble oxalates, which pose a higher health risk than insoluble ones, can dissolve and seep out of the grain and into the water. When this soaking water is discarded before cooking, a notable portion of the oxalates is removed.

The effectiveness of soaking depends on several factors, including the type of grain, the temperature of the water, and the duration of the soak. Studies have shown that soaking can reduce soluble oxalate content by a considerable margin. The process also activates phytase, an enzyme naturally present in grains that helps break down another antinutrient, phytic acid.

How to Maximize Oxalate Reduction

To get the best results from soaking, follow these steps:

Use Warm Water: Soaking in warm water can increase the rate of antinutrient reduction compared to cold water, speeding up the enzymatic process.
Add an Acidic Medium: Including a splash of lemon juice or a tablespoon of apple cider vinegar can further enhance the breakdown of antinutrients.
Proper Timing: While a few hours can help, a longer soak, such as overnight, is generally more effective for a thorough reduction. For grains, 12-24 hours is a common recommendation.
Discard and Rinse: Always drain and thoroughly rinse the grains after soaking. This is a critical step to ensure you remove the leached oxalates and other antinutrients from the food.

Comparison of Oxalate Reduction Methods

Soaking is just one of several methods for reducing antinutrients. Here is a comparison of different processing techniques:


Method	Mechanism	Effectiveness for Oxalate Reduction	Effectiveness for Phytate Reduction	Time Commitment	Notes
Soaking	Leaching soluble oxalates into water.	Good (40-77% reduction).	Minimal.	Moderate (overnight)	Requires discarding soaking water. Best for soluble oxalates.
Boiling	High heat and leaching into cooking water.	Excellent (30-87% reduction).	Excellent.	Moderate (12+ minutes)	Most effective for overall reduction. Requires discarding boiling water.
Steaming	Heat treatment and some leaching.	Good (42-46% reduction).	Good	Moderate	Preserves more nutrients than boiling but is less effective for oxalate reduction.
Fermenting	Microbial degradation of oxalates.	Excellent.	Excellent.	Long (days)	Often used for bread or other fermented grain products.
Sprouting	Enzymatic activity breaks down antinutrients.	Good	Excellent.	Long (days)	Increases nutrient content. Effective for both oxalates and phytates.

Specific Grains and Their Response to Soaking

Not all grains respond to soaking in the same way, due to differences in their chemical composition and structure.

Oats: Oats contain moderate levels of oxalates. Soaking them overnight, often with an acidic medium like yogurt, can help reduce their oxalate content, though cooking is still the most effective method.
Buckwheat: Often lauded for its health benefits, buckwheat has relatively high levels of soluble oxalates. Soaking is an effective first step, followed by rinsing and cooking, to minimize these compounds.
Amaranth and Quinoa: These pseudo-grains also contain oxalates. Soaking and rinsing prior to cooking is recommended to improve digestibility and reduce antinutrient levels.

Conclusion

Soaking grains does indeed reduce oxalates, particularly the more readily absorbed soluble oxalates. While other methods like boiling and fermenting may offer even greater reductions, soaking is a simple and effective preliminary step in food preparation. By incorporating soaking into your cooking routine, you can make a tangible difference in the antinutrient content of your food and enhance the absorption of essential minerals. It's a small change with meaningful nutritional benefits for those concerned with oxalate intake or mineral absorption. For personalized dietary advice, it is always recommended to consult with a registered dietitian or nutritionist. You can read more about antinutrients and food preparation techniques from authoritative sources like the NIH: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7600777/.

Authoritative Outbound Link

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7600777/

Disclaimer

The information provided in this article is for general informational purposes only and does not constitute medical advice. Please consult with a healthcare professional for specific health concerns or before making changes to your diet.

Frequently Asked Questions

For optimal reduction, soak most grains for at least 12 hours, and preferably overnight. Some people prefer a 24-hour soak for particularly high-oxalate grains, especially if an acidic medium is used.

No, you should never reuse the water used for soaking grains. The purpose of soaking is to leach out oxalates and other antinutrients, and reusing the water would simply reintroduce them to your food.

Soaking is beneficial for a wide range of grains and pseudo-grains, including oats, buckwheat, and quinoa. The degree of reduction varies based on the grain type and preparation method.

Cooking methods like boiling typically result in a more significant reduction of oxalates, but soaking is an excellent preparatory step. Combining soaking with cooking is the most effective strategy.

Yes, soaking can slightly decrease some water-soluble vitamins, but this is generally outweighed by the improved absorption of minerals like calcium, iron, and zinc. The overall nutritional benefits are enhanced.

For most people, nothing significant. However, for those sensitive to oxalates or prone to kidney stones, unsoaked high-oxalate foods may contribute to higher oxalate absorption and risk. Soaking is a precautionary measure.

Yes, fermentation is a highly effective method for reducing oxalates, as it relies on microbial activity to degrade these compounds. This is a traditional practice for making sourdough bread and other fermented grain products.